The demand for various wideband telecommunications services such as high resolution video, voice communications, and terminal and computer connections provides an impetus for the introduction of a broadband digital trunk and exchange network. One example of a broadband digital trunk and exchange network is known as the Broadband Integrated Digital Services Network (B-ISDN) (see e.g. L. R. Linnell, "A Wide-Band Local Access System Using Emerging-Technology Components," IEEE Journal on Selected Areas in Communications, vol. 4, no. 4, pp. 612-618, July 1986; D. R. Spears, "Broadband ISDN Switching Capabilities F. from a Services Perspective," IEEE Journal on Selected Areas in Communications, vol. 5, no. 8, pp. 1222-1230, October 1987).
Information transmitted across a broadband digital trunk and exchange network such as BISDN may be carried using the Asynchronous Transfer Mode (ATM) technique (see e.g. S. E. Minzer, "Toward an International Broadband ISDN Standard" Telecommunications, October, 1987 and Chao et al, "Dynamic Time Division Multiplexing," U.S. patent application Ser. No. 118,977 filed on Nov. 10, 1987 and assigned to the assignee hereof). In the ATM technique, data from various services are transmitted in fixed length cells, which cells are embedded in the payload envelopes of the frames which comprise the Synchronous Optical Network (SONET) STS-3c or STS-12c signals (see e.g. Draft of American National Standard For Telecommunications Digital Hierarchy Optical Interface Rates and Formats Specifications, T1X1.4/87-505R4, December 1987).
Many network issues such as packet transmission and multiplexing techniques (see e.g., H. J. Chao, "Design of Transmission and Multiplexing Systems For Broadband Packet Networks," IEEE Journal on Selected Areas in Communications, vol. 6, no. 9, pp. 1511-1520, December 1988), packet switching network designs (see e.g. C. Day, J. Giacopelli, and J. Hickey, "Application of Self-Routing Switches to LATA Fiber Optic Networks," in Proc. 1987 International Switching Symposium, Phoenix, Ariz. March 1987; T. T. Lee, "Nonblocking Copy Networks for Multicast Packet Switching," IEEE Journal on Selected Areas in Communications, vol. 6, no. 9, pp. 1455-1467, December 1988), and routing and flow control (see e.g. J. Y. Hui, "Resource Allocation for Broadband Network," IEEE Journal on Selected Areas in Communications, vol. 6, no. 9, pp. 1598-1608, December 1988) have been widely explored for broadband digital trunk and exchange networks such as B-ISDN.
Here, the concern is with the customer premises network. The customer premises network provides interface connections between a public broadband digital trunk and exchange network and the customer premises equipment or user terminals. The customer premises equipment includes devices such as telephones, fax machines, video display devices, and various types of computer terminals and workstations.
A customer premises network for use in connection with a broadband digital trunk and exchange network desirably has the following characteristics.
1. Multiple Priorities
Due to the different delay constraints for various services (e.g., video, voice, data), the access of the various services to the limited bandwidth in the customer premises network should be prioritized. For example, real time traffic such as video and voice are more delay-sensitive than data and should be assigned higher priority.
2. Uniform Access
The customer premises network should support a wide variety of services and all of the services should be carried using a single transfer technique such as ATM.
3. Asymmetric Traffic
Traffic in the customer premises network flows mostly between the external public trunk and exchange network and the customer premises equipment attached to the customer premises network. In particular, in residential applications, the amount of downstream traffic transmitted to the customer premises equipment via the customer premises network will greatly exceed the upstream traffic generated by the customer premises equipment. For example, the demand for multiple channel high quality residential video such as HDTV requires a transmission bandwidth of about 600 Mbits-sec in the downstream direction while a transmission bandwidth of about 150 Mbits/sec is required in the upstream direction.
4. Centralized Control Capability
An interface serving as a gateway between the public trunk and exchange network and the customer premises network is desirable for providing centralized control functions such as call setup, administration, maintenance, and flow control.
5. Flexibility
The customer premises network should be designed to accommodate changes such as the addition or relocation of particular units of customer premises equipment, which commonly occur in the customer premises environment.
6. Reliability
The design of the customer premises network should be sufficiently reliable to prevent an entire network from failure due to a malfunction in a single unit of customer premises equipment.
7. Economy
The customer premises network should be cost effective. Several architectures and associated access protocols have been proposed for the customer premises network. These include a token ring architecture using the FDDI protocol (see e.g. J. F. McCool, "The Emerging FDDI Standards," Telecommunications, May 1987), the METROCORE double unidirectional bus architecture and associated Fasnet protocol (see e.g. J. O. Limb and C. Flores, "Description of Fasnet--A Unidirectional Local Area Communications Network," BSTJ, vol. 61, no. 7, pp. 1413, September, 1982; A. Albanese et al, "Bellcore METROCORE Network--A Test-Bed For Metropolitan Area Network Research," Globecom queuing dual bus architecture and its associated QPSX protocol (see e.g. R. M. Newman, Z. L. Budrikis, and J. H. Hullett, "The QPSX MAN," IEEE Communication Magazine, vol. 26, no. 4, pp. 20-28, April 1988).
However, none of these prior art customer premises networks meet the desired characteristics for such networks as set forth above. For example, the FDDI token ring system mentioned above does not provide uniform access for all types of services. The METROCORE system and associated Fasnet protocol are highly inefficient because of the dead time between service cycles. This inefficiency is increased, when under uniform access conditions, high bit rate services such as full motion variable bit rate video are accommodated. In embodiments where the dead time is eliminated, this system is not able to provide uniform access for all services. The distributed queuing dual bus system mentioned above is highly complex in that each unit of customer premises equipment must be aware of the position of a desired destination unit of customer premises equipment in order to decide on which bus to send information. Thus, flexibility is hard to achieve in this architecture. In addition, different transfer techniques are used for different types of services, so that each unit of customer premises equipment is required to have hardware for more than one type of transfer technique.
In view of the foregoing, it is an object of the present invention to provide a customer premises network which meets the desired characteristics for customer premises networks set forth above. It is a further object of the invention to provide a customer premises network which utilizes ATM to deliver all services.